Solar power is an increasingly important power source in view of non-pollution, non-noise, and simplified maintenance aspects. However, solar panel output may be easily influenced by illumination intensity, environmental temperature, and load. In addition, solar panels may have non-linear characteristics, and the output voltage of the solar panel may differ even when illumination intensity and environmental temperature are relatively constant. As a result, a controlling circuit may be used to improve efficiency by tracking the maximum power point in order to control the output voltage of the solar panel. However, conventional solar panel power tracking circuits may be relatively complicated and expensive, and may not be applicable for large-scale solar panel arrays.